The huge key factor in the linked article is "warrants."
Rather than a mass collection of data on the off chance some number of things in the data might be useful sometime, this is a very targeted search for a very specific document discovered via a search with a properly issued warrant. There are checks and balances in the system for reasons. Currently, things have swung to far to "collect everything in case we need it!" On the other side of the spectrum is "Collect nothing. Privacy is absolute." Somewhere in the middle is the appropriate area that balances the needs of societal protection against individual privacy rights. That pendulum will always swing. Wherever it happens to be, some group will always be unhappy.